Fig. 7.
Impact of 10−5 M ryanodine on [Ca2+]i in isolated rat mesenteric collecting lymphatic vessels. A: traces of the F340/F380 ratio obtained over time from a single rat mesenteric collecting lymphatic vessel loaded with the Ca2+ indicator dye fura-2 AM before and after exposure to 10−5 M ryanodine (added at time 0 min). Changes in F340/F380 are indicative of changes in [Ca2+]i. B: measurements of luminal diameter obtained from the same lymphatic vessel during the same time periods. C: mean basal F340/F380 between Ca2+ transients from four collecting lymphatics during the baseline (BL) period before ryanodine treatment and the indicated times after ryanodine was added. Basal F340/F380 significantly increased over BL at 10–11 and 15–16 min after addition of ryanodine. D: mean frequency of Ca2+ transients, showing a significant mean reduction at 10–11 and 15–16 min after ryanodine was added. E: mean amplitude of the changes in F340/F380 for Ca2+ transients was significantly decreased at 15–16 min after ryanodine was added, mainly because of the disappearance of Ca2+ transients at this time point. F: basal diameter/MaxD (EDD/MaxD when phasic contractions were present) significantly decreased form BL at all time points after ryanodine was added. G: amplitude of phasic contractions significantly decreased from BL starting at 6–7 min after ryanodine was added. Lymphatics displaying no phasic contractions were assigned an AMP/MaxD value of 0 in this analysis. Data were analyzed by one-way repeated measures ANOVA followed by Dunnett’s test for multiple comparisons with control. P values for all significant difference are shown. N = 4 isolated mesenteric collecting lymphatics obtained from four different rats. EDD, end-diastolic diameter; MaxD, maximal passive diameter; NS, not significant.